Alright, first of the stock bypass valve is good untill you start making serious power and make big engine management changes. The 3SGTE is an awesome engine. Stock, all the internals are good for about 400 hp except the pistons. The stock fuel system is good for 285-300hp. Stock ignition is very good (the car eats thru ignition parts tho).Cooling is a problem with the midengine layout, so SPAL fans are a wise investment, as is some good water injection. If you want to start making serious hp, standalone engine managment is going to be a must because of timing issues and the need for a MAP instead of a MAF. Good turbo kits (as in quick spool up, low lag...)are the T3/T4, Extreme Boost GT25 kit, Blitz K1, and the CT20B from the 3rd gen 3SGTE are all popular choices. The Greddy intercooler is popular, but personally I like the Air/Water route. As far as suspension goes; alot of people like to go with the 93+ rear suspension. I like the 91-92. The turbo brakes from the 93+ are really good too. Bill's website is awesome too...